Valving for hydraulic power converter



Oct. 25, 1966 J. E. SMITH 3,280,833

VALVING FOR HYDRAULIC POWER CONVERTER Oct. 25, 1966 J. E. SMITH VALVINGFOR HYDRAULIC POWER CONVERTER 7 Sheets-Sheet 2 Original Filed Feb. 26.1962 Oct. 25, 1966 J. E.SM1TH VALVING FOR HYDRAULIC POWER CONVERTERoriginal Filed Feb. 26, 1962 '7 Sheets-Sheet 3 [myn/raie: JHM/55 f,iwf/f AQUI/Ml Z www 477'? P/VE VJ',

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Oct. 25, 1966 J. E. SMITH 3,280,833

VALVING FOR HYDRAULIC POWER CONVERTER Original Filed Feb. 26, 1962 7Sheets-Sheet 4 FIGS @Www/W @et 25, 1966 .1. E. sMrrH 3,280,833

VALVING FOR HYDRAULIC POWER CONVERTER Original Filed Feb. 26, 1962 7Sheets-Sheet 5 Oct. 25, 1966 J. E. SMITH 3,280,833

VALVING FOR HYDRAULIC POWER CONVERTER Original Filed Feb. 26, 1962 7Sllees--Sheei'r 6 f/V/f//faf 1 4M/es f. 5mm

J. E. SMITH 3,280,833

VALVING FOR HYDRAULIC POWER CONVERTER '7 Sheets-Sheet '7 Oct. 25, 1966Uriginal Filed Feb. 26; 1962 FIGB 3,280,833 VALVING FOR HYDRAULIC POWERCONVERTER James E. Smith, 302 Plantation Drive, Lake Jackson, Tex.Original application Feb. 26, 1962, Ser. No. 175,767, now

Patent No. 3,162,133, dated Dec. 22, 1964. Divided and this applicationDec. 21, 1964, Ser. No. 436,972

3 Claims. (Cl. 137-595) This application is a division of applicationSerial No., 175,767 filed February 26, 1962, now patent 3,162,133,issued December 22, 1964.

This invention relates to a hydraulic power converter for exertingpressure on abrasive uids so .that the fluids may be transmitted throughpipe lines. In particular, this invention rela-tes to an auxiliarydevice for pumping large quantities of such materials as coal, iron ore,woodchips, etc. mixed with water or other liquids under high pressure sothat the abrasive or lumpy material can be transported through pipesdire-ctly from deep mines or high mountains, or other places wheretransportation presents a problem of economics or accessibility therebyavoiding the necessity for the heavy equipment or expensive roads,trucks, trains, or other present day methods of transportationequipment, etc.

At the present time, such abrasive, or heavy, lumpy materials are pumpedat limited pressure. However, for economically moving these slurries,much is to be desired in more efficient equipment, since conventionalpumps wear out rapidly, especially under high pressure. For this reason,the pumping of such materials is not in widespread use.

One of the principal objects of the present invention is -to provide adevice which -allows abrasive or solid laden Huid to be pumped withoutsaid fluid or slurry having to pass through the pump itself.

Another object is to increase the pressure on large quantities fabrasive fluids by using relatively large cylinders with slow movingpistons to reduce wear.

Another object is to provide a device for pumping said abrasive iluidthrough plunger valves which operate relatively infrequently, but movevery fast when they -are operating so as to cut 4or chop up any objectwhich might tend to cause a conventional valve to stick or becomejammed.

A further object is to provide a device in which there is some play orflexibility between a double headed piston and the central connectingshaft to prevent interruption of the lcontinuous operating iluid fromthe pump, and to prevent pulsation during pumping.

Another object is to provide a hydraulic device wherein the valvesoperate 'by hydraulic power against the discharge pressure of iluid fromthe converter and are so constructed and arranged to hold and sealagainst said pressure, with the pressure being exerted through the pipeline leading from the converter. This is accomplished through the use ofactuating spool valves of greater effective diameter than the openingwhich receives the plunger valve.

A further object is to provide an auxiliary pumping device fortransmitting large quantities of abrasive material in a iluid slurrywherein fast acting plungers, acting as valves are provided withhardened cutting inserts and heads adapted to chop up and cut 4throughany solid foreign matter which may be lodged in the path of the plunger,or piston valve.

Still another object is to provide a hydraulic power converter deviceoperated by a pressure pump and adapted to transmit highly abrasive orsolid laden fluids for long United States Patent O 3,280,833 PatentedOct. 25, 1966 ice distances through a high pressure pipe line withoutundue wear on the pumping components powering the device.

Another object is to provide a hydraulic power converter wherein :themoving main piston controls the movement of a switching valve whichdirects the high pressure uid from the operating power pump to the spoolvalve chambers of the intake and exhaust plunger valves, which in turnchange the direction of, or reverse the direction of fluid ow into themain chambers or cylinders to reciprocate the main pistons back andforth, and at the same time, reverse :the positions of the plungervalves.

Still a further object of the present invention is to provide a doubleheaded plunger valve including a center control portion adapted toalternately receive fluid under pressure in spaced expandable chambersto drive said valve along a fixed casing and to hold said valve in itsseat. Another object is to provide a plunger valve as described whereinthe heads and cooperating seats are constructed of hardened matingsurfaces to chop through solid matter which may be lodged in the path ofthe moving valve head.

A further object of the present invention is to provide a piston headand rod having limited predetermined longitudinal movement therebetween.Another object is to provide a tiexible piston rod and head as describedwherein a resilient means is trapped between internal shoulders on thehead and the end of the rod to give limited longitudinal movementbetween the rod and the head.

These and other objects and advantages will become apparent hereinafter.

The present hydraulic power converter comprises a relatively largecylindrical chamber for receiving pumped iluid on the inside of a pistonand abrasive containing fluid on the other side, said piston headcooperating with inlet and outlet valves which move relativelyinfrequently but very rapidly, said valves being provided with heads ofhard material which pass through :a ring of like material so as to chopthrough any abrasive or solid material which might tend to clog theValve, or plunger opening, said main piston heads being secured to acentral shaft with flexible play provided therebetween to preventpulsation or interruption of total ilow from the operating pump.

The invention also consists in the parts and in the arrangements andcombinations of parts hereinafter described and claimed.

In the accompanying drawings which form part of this specification andwherein like numerals and symbols refer to like parts wherever theyoccur:

FIG. 1 is a .top plan View of a hydraulic power converter embodying thepresent invention and showing the flow path of the pumped fluid indotted lines with arrows thereon,

FIG. 2 is an end view of the device,

FIG. 3 is a longitudinal cross-sectional View taken along the line 3 3of FIG; 2,

FIG. 4 is an enlarged broken sectional view taken along line 4 4 of FIG.5v,

FIG. 5 is Van enlarged cross-sectional view taken along the line 5 5 ofFIG. 4,

FIG. 6 is an enlarged sectional view taken along line 6 6 of FIG. 5,

FIG. 7 is an enlarged broken cross-sectional View of the end housingshowing the left piston at its outermost position and showing the inletand outlet valves for .the pumped uid,

FIG. 8 is a sectional View taken along the line 8 8 of FIG. 7,

FIG. 9 is an enlarged cross-sectional view taken along line 9 9 of FIG.4,

.FIG. is an enlargedbroken sectional view showing the details of one ofthe valves controlling the ow of the pumped fluid in its open position,

FIG. 11 is an enlarged broken sectional view of the valve shown in FIG.10 in its closed position, and,

FIG. 12 is a diagrammatic representation of the flow path of the pumpingfluid.

Referring now to` the drawings in detail, it will be seen that theembodiment of the invention which has been illustrated comprises ahydraulic power converter 10 having a central portion 11 with two largealigned cylinders 12 and 13 therein,- and .two valve casings 14 and 15parallel to said cylinders 12 and 13. The converter 10 is mounted on abase 16. End housings 17 a-nd 18 are positioned on the outer ends of thecylinders 12 and 13 and also enclose the ends of the Valve casings 14and 15.

The central portion 11 is provided with a central housing 19 with thetwo relatively large cylinders 12 and 13 extending in opposi-tedirections therefrom. The central housing 19 is provided with a bearing20 for receiving a central shafto'r piston rod 21 having flexible pistonheads 22 and 23 mounted at both ends thereof. The central shaft 21 isslidable in said bearing 20. Each of the exible piston heads 22 and 23(FIG. 7) comprises an annular portion 24 with a seal 25 secured theretoin circumscribing relation. A hollow central cap 26 is secured to theannular portion 24 to form .a chamber 27 for receiving a small piston 28secured to the end of the central shaft 21 with a spring 29therebetween. The spring 29 is positioned between a shoulder 30 in thesmall piston 28 and a shoulder 31 in the annular member 24'.l Thisarrangement allows sorne play between the central shaft 21 .and thepiston heads 22 and 23.

In other words, the shaft 21 and the small piston 28 can movelongitudinally with respect to' the annular portion 24 and the cap 26 bycompressing the spring 29 between .the shoulders 30 and 31. Similarly,the shaft 21 and the small piston 28 can remain stationary, while theannular portion 24 and the cap 26 are moving longitudinally b'ycompressing the spring 29.

The two valve casings 14 and 1S are similar to each other and extend inparallel relation with the central cylinders 12 and 13 on either .sidethereof. The valve casing-s 14 and 15 comprise oppositely extendingportions 14a, 1417, 15a and 15b on either side 'of :the central portion11 to provide a relatively long hollow cylindrical valve casing.

Although the inlet valve casing 14, the cylinders 12 and 13, the outletvalve casing are shown as being hori- Zontally aligned, it iscontemplated that they can be vertically aligned, ie., the intake Valvecasing 14 can be positioned above the cylinders 12 and 13, and theoutlet valve casing 15 can be positioned below the cylinders 12 and 13.This configuration is preferred when fluid containing heavy particles(such as ore or chat) is being transmitted, since gravity will assist inpassing the heavy particles through the converter 10. Also, the inletvalve casing 14 can be below the cylinders 12 and 13, and the outletvalve casing 15 can be above the cylinders 12 and 13. This conigurationis desired when particles lighter ,than the uid (such as woodchips) arebeing` transported, since the light particles will tend to float throughthe converter 10.

The valve casing 14 houses the intake control valve as# ser'nbly 32 andthe v-alve casing 15 houses the outlet or exhaust control valve assembly33. Each of the valve assemblies 32 and 33 is provided with la maincontrol piston portion 34 and 35, respectively, which is slidablelongitudinally through the central portion 11 and has a valve rod 36extending from each end thereof. Each of said valve rods 36 pass throughfixed bushings 37 and 38 and has Ia valve head 39 or 39a on the .leadingend thereof. The valve heads 39 are part of the intake valve assembly32, while the valve heads 39a are part of the exhaust Y detail.

valve assembly 33. Each valve head 39 or 39a is rel-atively long andslides on a machined surface 40 in the: outer ends of the valve casings14a, 1419, 15a, and 15b- Each of the valve heads 39 and 39a (FIGS. 10and! 11) is provided with a very hard steel insert plate 41E on theforward or cutting edge 4thereof and is provided. with a suitable seal42 around the outer periphery there-- of. The steel insert plate 41 isin aligned relationi with a very hard steel valve seat 43 mounted in theend housing 17. A seal member 44 having an annular open-4 ing 45 of-less diameter than the steel insert plate 41 is po-A sitioned in theend housing 17 outwardly of the valve seat 43 `and is adapted to sealthe outer end of the valve: head 39 after it has passed through thevalve seat 43` against back pressure as will be explained more fully'hereinafter (FIG. 11). The back pressure tends to force: the seal 44into tight compression around the outer pe riphery of the end of theplate 41. Since the seal 44 is'y positioned at the outer end of thestroke of the valve4 head 39, .there is very little wear on the seal 44caused by the back and forth movement of the valve head 39.. Alretaining plate 46 holds the outer seal 44 in place.,

The main control portion 34 of the intake valve assembly' 32 is similarto the main control portion 35 ofi' the exhaust valve assembly 33, andtherefore only the: intake valve assembly control 34 will be describedin'. The valve assemblies 32 and 33 move in op posite directionssimultaneously during functioning of the; present invention.

The main control portion 34 of the intake valve as sembly 32 (FIG. 4)includes a left piston comprising an. annular plate 47 carrying a seal48 on the outer peripheryl thereof and a stepped plug 49 secured .to.the outermost: face thereof. The plate 47 and plug 49 define aneffective piston surface in face-to-face relationship with the innermostxed bushing 37. The plug 49 includes. a projection 50 adapted to bereceived in a counterbore 51 in the bushing 37. The bushing innersurface includes a tapered surface 52 and a flat surface 53 connecting;the counterbore 51 and the tapered surface 52. The: piston surface andthe bushing surface define an expandable annular chamber 54 with theinner surface of .ther valve casing 14a. The piston rod 36 extends fromthe. projection 50 and rides in the Abushing 37.

The center portion of the valve control 34 includes:

a pair of annular lreduced sections 55 and 56 spaced by a solid core 57carrying a seal 58. The right-hand part of the inlet valve control 34includes a right piston comprising an annular plate 59 carry-- ing aseal 60 on the outer periphery thereof and a stepped'. plug 61 securedto the outer face thereof. The pistoni defines an Aeffective pistonsurface in face-to-face relation ship with the innermost xed bushing 37.The plug 61 irl-- cludes a projection 62 adapted to be received in acoun-- terbore 63 in the bushing 37 The bushing inner surface: includesa tapered surface 64 and a Hat surface 65 con-- necting the counterbore63 and the tapered surface 64.A The piston surface and the bushingsurface define an expandable annular chamber 66 with the inner surfaceofI the valve casing 14b. The piston rod 36 extends from the projectie-n62 and rides in the bushing 37.

The entire main valve control portion 34 is a unitary assembly and movesleftwardly and rightwardly .to carry' the valve heads 39 into and out ofthe valve seats 43.

The effective pressure receiving area of the piston surface ydefined bythe plate 47, the plug 49 and the projection 50 is greater than theeffective pressure receiving area of the left-hand valve head end plate41. Similarly, the effective pressure receiving area of the pistonsurface defined by the plate 59, the plug 61 and the projection 62 isgreater than the effective pressure receiving area of the right-handvalve head end plate 41.

Thickened connecting rods 67 and 68 connect the core 57 with the annularplates 47 and 59 and ,the rods 67 and 68 are greater in diameter thanthe piston rods 36.

The left and right end housings 17 and 18, respectively, cover `the endsof the cylinders 12 and 13 and the ends of the valve casings 14 and 15.The end housings 17 and 18 are similar and only the left end housing 17will be described in detail.

As may be seen from FIGS. 3 and 7, the left end housing 17 is providedwith an intake port 69 adapted to receive a conduit 70 carrying pumpedtluid. The port 69 communicates lwith the intake valve casing 14a. Theend housing 17 further deiines an annular passage 71 wherein are locatedthe valve seat 43 and the seal means 44.

A cover member 72 is secured to the end housing 17 and denes an intakecha-mber 73 which communicates with the annular passage 71. A passage 74communicates the chamber 73 with a main end chamber 75 which is alignedwith the left cylinder 12 and in communication therewith.

A connecting passage 76 communicates the main end chamber 75 an-d theleft cylinder 12 with the exhaust valve casing 15a `and with an annularpassage 77 which is aligned with the valve casing 15a and houses thevalve seat 43 and the seal 44.

A cover member 78 is secured to the end casing 17 and delines an outletchamber 79 which communicates with the annular passage 77, when theexhaust valve 39a is open,

An outlet port 80 communicates with the outlet chamber 79 and is adaptedto receive a conduit 81 for pumped fluid from the converter 10.

The pumped -tluid containing the large chunks of 'abrasive material ispicked up from its sounce through the cond-uit 70 when the inta-keva-lve head 39 is retracted and the intake port 69 is open. The tiuidpasses through the intake port 69, the annular passage 71, the endchamber 73, the passage 74 `and is pulled into the main chamber 75 andthe left cylinder 12 as the left piston 22 is moved rightwardly. Whenthe cylinder 12 is full, the intake valve 39 closes and the exhaustvalve 39a opens and, as the left piston 22 is moved .leftwardly, thefluid is pumped out of the cylinder 12 through the end chamber 75, thepassage 76, the annular pasage 77, the outlet chamber 79 and the outletport 80 to the conduit `81. The control for the piston 22 and the valves39 and 39a will be described in more detail hereinafter.

The operation of the right-hand portion of the converter is similar tothat hereinbefore described for the left-hand portion, but is in anopposed sequence. In other words, when the lleft piston 22 is pushing orpumping huid, the right piston 23 is on its intake stroke and pullingliuid into the cylinder 13. Also, when the left intake valve 39 isclosed (during the pumping stroke), the right intake valve 39 is open.Similanly, when the left outlet valve 39a is open (during the outletstroke), the right outlet valve 39a is closed.

As may be seen from FIG. 1, the pumped fluid is passed from its sourcethrough la main inlet conduit 82, which branches into the intakeconduits 70 which connect to the converter pumped fluid intake ports 69.The branch converter outlet conduits 81 from the converter outlet ports80 join into a main outlet .conduit 83 for pumped fluid.

Therefore, the valve heads 39 and 39a operate against the flow of pumpedlluid and the seal means 44 se-als the black pressure of the pumpedfluid. Also, the closed out-let valve head 39a (the left valve head 39ain FIG. 3) is sealed against the back pressure of the pumped uid whichacts on the closed valve head 39a through the branch conduit 81.Therefore, both of the closed valve heads 39 and 39a `are sealed againstthe back pressure of the pumped Huid. The seal means 44 -must have anannular openin-g 45 of less diameter than the diameter of t'he valveheads 39 and 39a to effectively seal against the outer periphery of thevalve heads 39 and 39a as shown in FIG. 7 for the exhaust valve 39a.

The operation of the piston heads 22 and 23 and the valve heads 39 and39a is controlled by `a suitable system of openings, passages, conduitsand ports which are 4provided for the pumping fluid which is pumped inadequate quantities and pressure from a pump 84 which is capable offurnishing large quantities of pumped Huid under extremely highpressure. The pressure required of the pump 84 is determined by thedensity of the pumpe-d uid, the distance it must be moved, the pressurehead desired, and the height it is raised. The ow ydiagram for thepumping Huid is diagrammatically shown in FIG. 12.

The discharge side of the pump 84 is connected to a main conduit 85which bnanches into a three-Way connection so that the pumped iluid isdelivered simultaneously into three sepa-rate conduits 86, 87 and 88.The conduits 86 and 87 connect to ports 89 and 90 provided in the centerportion 11 of the converter 10 (FIGS. 3 and 4). The ports 89 and 90communicate with the intake valve casing 14 and are aligne-d withpassages 91 and 92 which communicate with the cylinders 12 and 13,respectively.

The main control portion 34 of the intake valve assembly 32 ispositioned so that it reciprocates the reduced portions 55 Iand 56between the ports y89 and 90 and the passages 91 and 92 to alternatelyestablish and interrupt communication between said ports 89 and 90 andthe passages 91 and 92, respectively. Thus, when the intake valve 32 isin its rightward position (as shown in FIG. 3) the conduit 87 deliverspumping fluid from the pump `84 to the intake port 90 from whence it ispassed by the reduced portion 55 to the passage 92 and into the rightcylinder 13 where it urges the right piston 23 outwardly to pump t-hefluid in the cylinder 13 to the pumped uid outlet conduit 81. v

The exhaust valve 33 meanwhile is in its leftward position (FIG. 3) sothat the fluid previously located in the left cylinder 12 behind theleft piston 22 is exhausted through a pass-age 93 in the central portion11 of the converter 10 around the reduced portion 56a of the exhaustpiston control 35 through an outlet port 94 and to an exhaust conduit 95which is connected to the intake side of the pump 84, thereby providingcontinuous closed circuit flow of the pumping fluid.

A passage 96 in the converter lcentral portion 11 cornmunicates theright cylinder 13 with the exhaust piston casing 15 and with an outletport 97 which also is connected to an outlet conduit 98 and to t-heintake side of the pump 84, thereby providing a path for exhausting thepumping fluid from the right cylinder 13 behind the piston 23, when thepiston 23 is moved leftwardly after the exhaust valve assembly 33 hasbeen moved to its rightward position. When the exhaust valve assembly 33is in its rightward position, the reduced portion 55a thereofcommunicate the port 97 with the passage 96.

Thus, it is seen that the pump 84 maintains a continuous pressure in thebranch conduits 86 and 87 and that the movement of the control portions34 and 35 of the valve assemblies 32 and 33 determines the path which istaken by the pumping fluid Iand therefore determines vhih of thecylinders 12 and 13 receives the pressurized The position of the valveassemblies 32 and 33 determines the path of ow of the pumping fluid tothe main cylinders 12 and 13 and thus determines the direction ofmovement of the pistons 22 and 23. However, the movement of the valveassemblies 32 and 33 themselves is controlled by a switching spool valve99 which is responsive to movement of the piston heads 22 and 23 and ispositioned on the outer surface of the central portion 11 and includes acylinder 100 provided with an inlet port 101 and spaced outlet ports 102and 103. A slidable piston 104 is positioned within the cylinder 100 andcontrols and switches the flow of tiuid from the intake port 101 to theoutlet ports y1'02 and 103. The piston 104 includes a reduced portion105 in the center thereof and is urged 'downwardly against the outersurface of the lcentral portion 11 by resilient means such as a spring106 which is compressed between one end Vof the valve 99 and the upperend of the piston 104. A pin 107 is xed 'to the lower end of the piston104 a'nd extends downwardly through the converter 4central portion 11into a chamber 108 provided therein. The 'chamber 10S is open to thevleft cylinder 12. A pusher cam 109 is positioned within the chamber 108and includes a main body portion 110 which is connected to a thin noseportion 111 by a tapered cam surface 112. A plug 113 is secured to thefree end of the nose 110 and rides in a pocket 114 in the centralportion 11, said pocket being open to the right cylinder 13. The 1cammember 109 is positioned within the cylinder 108 so as to protrudealternately beyond the outer surfaces of the converter central portion11 into the cylinders 12 and 13.

The ends of the cam member 109 are engaged by the inner surface of thepistons 22 and 23 immediately prior to their engaging the inner surfacesof the central portion 11. When the piston which is moving in thecylinder which is being exhausted of pumping fluid engages the end ofthe cam 109 which is protruding into said cylinder, the cam member 109is moved in the same direction as the piston is moving, and the rod 107rides up or down the tapered surface 112 to move t-he spool piston 104correspondingly, and thus switch the path of the pumping uid between theoutlet ports 102 and 103.

The spool valve inlet 101 is connected to the conduit 88 which deliverspumpingflu'id thereto.

As shown in FIGS. l1, 2 and 9, the uppermost control valve outlet port102 `is connected to a conduit 115 which branches into conduits 116 and117 which are connected to inlet ports Y118 and 119 which communicatewith the annular chambers 66 and 54a in the valve casings 14 and 15,respectively. Similarly, the lowermost outlet port 103 is connected to aconduit 120 which branches into conduits 121 vand 122 which connect toinlet ports 123 and 124 communicating with the annular chambers 54 and66a in the valve casings 1'4 and 15, respectively.

The outlet conduits 125, 126, 127 and 128 Yfrom the annular chambers 54,4V66, 54a vand 66a are all connected to the intake side of the pump y84and define a closed circuit for the pumping fluid.

Thus, it is seen that the ow of fluid to the valve casings is controlledby the Amovement of the main pumping pistons 22 and 23. However, onceJthe ow of fluid to the valve assembly control portions 34 and 35 isreversed or switched lby the movement of the control valve 99, thedirection of ow of pumping fluid tothe cylinders 12 and 13 is reversed,and thus the direction of travel of the pistons 22 and 23 also isreversed. The movement o'f the pistons 22 and 23 is relatively slow,being on the order of four to five reciprocating movements per minute,whereas the movement of the control valves 32 and 33 is relatively fast,so that the hard steel inserts 41 tend to cooperate with the valve seats43 to cut or chop through any solid matter which may become lodged inthe valve casings 14 and 15 and therebyl prevent interruption of theflow of pumped fluid through the converter y10.

Also it is seen that momentarily 'there may be a flow of pumping fluidinto both cylinders 12 and 13 during the time that the spool valve 99 isshifting. The resilient construction of the piston heads 22 and 23prevents pulsation and interruption 'of flow of the pumping iiuid andconsequent interference with the pumping action of the pump 84. Alsothere may be a slower movement of the valve assemblies 32 and 33 duringtheir initial phase of movement, since the pumping Huid is exerting aback pressure against the annular plates 47, 47a, 59 and 59a which mustbe overcome by the larger pressure receiving surfaces within theannularchambers 54, 54a, 66 and 66a. However, once the valve assemblies 32 and33 begin to move to their new position, they move very rapidly to '8provide 'the intense cutting force which `is necessary when particles ofcoal, etc. are being pumped and must be chopped through.

The flow of the pumped uid is shown by the arrows and dotted 'lines inFIG. l wherein the abrasive containing uid comes into the converter 10from a single source at the upper left an-d upper right; is pumped bythe pistons 22 and 23; lleaves through the outlets at the lower left andlower right; and then is directed to a single pipe 83. Each of thecylinders 12 and 13 has an inlet valve 39 and an outlet valve 39a.During the intake stroke, the intake piston moves from its outermostposition to its innermost -position with the cylinder thereby taking inabrasive Huid through the open inlet valve 39. When the piston reachesits innermost position, it moves the pusher cam 109 and thereby reversesthe flow of pumping fluid to the valve control ports so that the inletvalve 39 closes very rapidly and positively, since it chops or cuts itsway through any foreign material that might otherwise tend to clog theclosing of the inlet valve. Simultaneously therewith, the outlet valve39a opens and the piston begins its reverse stroke and moves toward theouter end of its cylinder, due to the pressure of the uid from theoperating pump, thereby forcing the abrasive fluid out through outletvalve 39a in large quantity under high pressure.

To recapitulzlte a complete cycle of the flexible piston heads 22 and23, i.e., a complete leftward and rightward movement, I start with theleft piston 22 in its leftmost or outermost position (as shown in FIG.7). In this position, the right piston 23 yengages the plug 4113 andmoves the pusher cam 109 to its left position (FIG. 6) and the spoolvalve 99 drops to its lowermost position to connect the inlet 101 to thelower outlet 103 whereby pumping fluid is passed to the conduits 121 and122 and through the ports 123 and 124 into the valve casing chambers 5.4and 66a. The inlet valve assembly 32 moves to its rightward position(FIG. 3) because of the flow of pumping fluid into the valve casingchamber 54 and opens the left inlet port 69 for pumped tluid and closesthe right pumped uid inlet port 69a. The rightward movement of the inletvalve 32 also establishes communicati-on between the pumping fluid inletport and the right cylinder 13 through the passage 92 and the reducedportion 55 of the inlet valve control port-ion 34. The rightwardmovement of the inlet valve 32 also interrupts communication between thepumping fluid conduit `86 and the left cylinder 12 lby positioning thecore S7 between the inlet port 89 and the passage 91. The flow ofpumping uid into the right cylinder 13 behind the piston head 23 tendsto move the right piston 23 outwardly toward its rightward positionimmediately subsequent to the movement of said intake valve assembly 32.Thus, the in-let valve assembly 32 moves in the same direction andimmediately before the subsequent movement of the piston heads 22 and23.

Simultaneously with the rightward movement of the intake valve 32, theoutlet valve assembly 33 moves leftwardly (PIG. 3), since the pumpingfluid in the conduit 122 is passed to the valve casing chamber 66a andthe conduit 117 is cut 01T from the valve casing chamber 54a. Theleftward movement of the exhaust valve 33 closes the left outlet pumpedfluid port 80 and opens the right outlet pumped uid port 80a. Theleftward movement of the valve 33 also establishes communication betweenthe left cylinder 12 land the pumping fluid outlet conduit bypositioning the reduced portion 56a between the passage 93 and the port94. Communication between the right cylinder 13 and the outlet conduit98 is interrupted, since the core 57a is positioned between the passage96 and the port 97. The rightward movement of the left piston 22 forcespumping fluid from the left cylinder 12 through the passage 93 into theoutlet conduit 95 and to the intake side of the pump 84. Thus, theexhaust piston assembly 33 moves immediately before and in the oppositedirect-ion from the pistons 22 and 23.

The foregoing described condition holds during the rightward movement ofthe pistons 22 and 23 (FIG. 3).

When the left piston 22 reaches its innermost or rightward position(indicated by the lbroken lines in FIG. 3), it engages the ybody 110 ofthe -pusher cam 109 and moves the pusher cam 109 rightwardly, raisingthe spool piston 104 to establish pumping fluid fiow through the inletport 101 to the uppermost outlet 102 and to the conduits 116 and 117.Accordingly, the fluid is passed to the valve cas-ing chambers 66 and54a and is shut off from the valve casing chambers 54 and 66a. Thus, theinlet valve 32 moves leftwardly, and the outlet valve 33 movesrightwardly. Simultaneously, the flow of pumping fiuid is cut off lfromthe right cylinder 13 and is passed to the left cylinder 12 therebymoving the left piston 22 leftwardly to push the pumped fluid out of theleft chamber 12 to the discharge conduit 83. The right piston 23 also ismoved leftwardly adn pulls pumped fluid into the right cylinder 13.Also, the flow paths for the pumping uid from the cylinders 12 and 13 tothe outlet conduits 95 and 98 are reversed by the leftward movement ofthe outlet valve 33. Communication is established between the rightcylinder 13 and the conduit 98 to exhaust pumping fluid from the rightcylinder 13 to the intake side of the pump 84; .and communication isinterrupted between the left cylinder 12 and its discharge conduit 95.

The foregoing cycle is repeated as the converter is operated.

Any adequate source of pressurized fluid, the fluid preferably being oilor a mixture of oil and water, can be used to supply sufficient pumpingfluid to the central portion of the present hydraulic power converter10. This converter 10 does not pump by itself but requires a source 0fpressurized liuid, such as the pump 84, in order for it to perform Iitsoperation.

By using the converter 10, large quantities of abrasive material arepumped in large cylinders with slow moving piston heads, therebyreducing wear. This arrangement further requires only a few movements ofthe inlet and outlet valves per minute thereby reducing wear, ascompared to a conventional pump wherein small chambers are used withrapidly moving pistons and valves. The present piston heads are flexibleto permit some give to prevent pulsation and the interruption of ow. Theinlet and outlet valves are specifically designed to prevent wear andclogging.

Thus, it is seen that the present invention provides a hydraulic powerconverter for pumping large quantities of abrasive fluids at highpressures which achieves all of the objects and advantages soughttherefor.

This invention is intended to cover all changes and modifications of theexamples of the invention herein chosen for purposes of the disclosurewhich do not consitute departures from the spirit and scope of theinvention.

What I claim is:

1. A valve assembly comprising an elongated casing, a rst pair ofbushings -fixed on the ends of said casing, a valve rod slidable throughsaid bushings, valve heads positioned on the ends of said rod, valveseats spaced outwardly from said heads to define a port therebetween,said valve seats each having a central opening aligned with the valveheads, said valve heads adapted to slide longitudiinally in said casinginto said seat openings to alternately closely each -of said ports,sai-d valve heads 4and valve seats have hardened cooperating cuttingsurfaces adapted to cut through any `solid material which may be lodgedtherebetween, and a control portion between said heads, said controlportion dening a pair of opposed expandable chambers with a second pairof fixed Ibushings and a core fixed on the rod therebetween said rodalso slidable through said second pair of fixed bushings, said chambershaving means adapted to be connected alternately to a source ofpressurized uid to move said core, said valve heads and said rodlongitudinally through said casing.

2. The valve defined in claim 1 wherein seal means are positionedoutwardly of said valve seats, each seal means having an opening of lesssize than its respective said valve head, said valve head entering saidseal opening when it closes its port, said seal means being compresedtightly around the outer periphery of said valve head to seal said portagainst back pressure.

3. A sli-dable piston-like valve assembly comprising a cylinder, a rod,a piston head on one end of the rod and slidable in the cylinder,control means for reciprocating the piston in the cylinder, said meanscomprising an expansible chamber having one Wall fixed to the rod andanother wall fixed in the cylinder, said chamber being adapted to beconnected to a source of pressurized fluid to move the piston head inthe cylinder, said piston head having a hardened leading edge, and ahardened piston seat in the end of the cylinder aligned with the pistonand spaced therefrom to define `a port therebetween, said seat having acentral opening through which the piston head is movable to close thesaid port, seal means around the outer periphery of the piston, andannular seal means outboard Iof the seat and having a central openingaligned with the piston head .and the seat, said opening Ibeing of lessdiameter than the diameter of the piston head, said piston head beingmovable through the seat opening into sealing engagement with theannular seal means to seal said port against back pressure.

References Cited by the Examiner UNITED STATES PATENTS 2,087,185 7/1937Dillon 251-367 X 2,645,449 7/1953 Gulick 251-360 X 2,971,533 2/1961Bauerlein 137--595 X M. CARY NELSON, Primary Examiner.

H. KLINKSIEK, Assistant Examiner'.

1. A VALVE ASSEMBLY COMPRISING AN ELONGATED CASING, A FIRST PAIR OFBUSHINGS FIXED ON THE ENDS OF SAID CASING, A VALVE ROD SLIDABLE THROUGHSAID BUSHINGS, VALVE HEADS POSITIONED ON THE ENDS OF SAID ROD, VALVESEATS SPACED OUTWARDLY FROM SAID HEADS TO DEFINE A PORT THEREBETWEEN,SAID VALVE SEATS EACH HAVING A CENTRAL OPENING ALIGNED WITH THE VALVEHEADS, SAID VALVE HEADS ADAPTED TO SLIDE LONGITUDINALLY IN SAID CASINGINTO SAID SEAT OPENINGS TO ALTERNATELY CLOSELY EACH OF SAID PORTS, SAIDVALVE HEADS AND VALVE SEATS HAVE HARDENED COOPERATING CUTTING SURFACESADAPTED TO CUT THROUGH ANY SOLID MATERIAL WHICH MAY BE LODGEDTHEREBETWEEN, AND A CONTROL PORTION BE-